Kinetic and geometric determination of the growth morphology of bulk crystals: Recent developments

During their growth crystals adopt a variety of habits due to differences in relative growth rates of faces of which the crystal is composed. According to most crystal growth theories, the as grown crystal morphology is dominated by the slow-growing faces because the fast-growing faces may “grow-out” and not be represented in the final crystal habit. In this paper a survey is given of the recently developed correspondence between the evolution of various surfaces, their relative growth rates and the crystallographic structure of the crystal. In particular, it is shown that even fast-growing faces may increase their sizes and can encompass the crystal, while the slow-growing faces may decrease and disappear from crystal morphology. Therefore, the morphological importance of faces is not always inversely proportional to their growth rates. Such behaviour of growing surfaces influences the growth and evolution of both low- and high-index faces. For the same reasons, the faces of the largest interplanar distances are not necessarily the largest faces in the Bravais-Friedel-Donnay-Harker morphology. This paper explains some peculiarities of the crystal morphology deduced from the Bravais-Friedel-Donnay-Harker law and shows that the crystal geometry influences morphological importance and stability of faces to a great degree. The paper concludes with a future outlook and goals in this field of research.